Apparatus for displaying a stereoscopic two-dimensional image and method therefor

ABSTRACT

An apparatus for displaying a stereoscopic two-dimensional picture includes a display unit having a flat image display screen for displaying a two-dimensional picture containing a stereoscopic image; and an image transmitting panel placed parallel to and apart from the image display screen. The image transmitting panel has a microlens array of a plurality of lenses and an effective area larger than that of the stereoscopic image contained in the two-dimensional picture, and a lens frame area surrounding a perimeter of the effective area of the microlens array. The image transmitting panel generates an image-formation plane for displaying a real image of the two-dimensional picture in a space located on an opposite side to the display unit with respect to the microlens array.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an apparatus for displaying a two-dimensional picture containing a stereoscopic image and a method therefor.

[0003] 2. Description of the Related Art

[0004] As a way of reproducing a stereoscopic image, there is a method using polarizing glasses in which a viewer wearing the polarizing glasses observes right and left parallax images of the picture corresponding to the polarized, which are states different from each other. However, there is a troublesome disadvantage in such a method because the viewer has to wear polarizing glasses whenever he views the picture, in addition to preparation of two parallax images thereof.

[0005] As to a method that does not use any polarizing glasses, a method for displaying a stereoscopic image using a lenticular lens is known. In such a method using the lenticular lens, a picture composed of a pair of striped images arranged alternately as right and left parallax images corresponding to right and left eyes of the viewer is displayed on the display screen. The lenticular lens is provided on the viewer's side of the display screen so as to give directivity of each stripe pixel of the parallax images toward the corresponding eye, thereby enabling the viewer to recognize a stereoscopic image. However, there is a disadvantage of the lenticular lens method in that resolution is reduced by 50% when the stereoscopic image is displayed, in addition to complicated structure thereof.

[0006] Japanese Patent Kokai Hei 10-221644 discloses an improved apparatus for displaying a stereoscopic image with a lenticular lens which is designed to prevent unnecessary reflected light on the display screen and to reduce moiré and color drift in the reproduced picture. In such a displaying apparatus, polarizing means is utilized in such a manner that a pair of polarizing plates each having polarizing stripe polarizing axes in the orthogonal direction to each other are suitably arranged alternately together with the display screen and the lenticular lens in a predetermined direction and at a predetermined pitch. The viewer can visually observe a stereoscopic image through the polarizing plate.

[0007] In view of the foregoing descriptions, it is apparent that all of these conventional stereoscopic image display apparatuses require two parallax images corresponding to both eyes of the viewer in the beginning stage of photographing for the picture to be displayed. Therefore, the conventional stereoscopic image display apparatuses naturally demand many steps and means for supplying parallax images for the stereoscopic image.

OBJECT AND SUMMARY OF THE INVENTION

[0008] The present invention is made to overcome such a conventional problem and therefore an object of the present invention is to provide an apparatus for displaying a stereoscopic two-dimensional image which solves such problems and realizes the display of a stereoscopic image using a simple configuration.

[0009] An apparatus for displaying a stereoscopic two-dimensional picture according to the present invention comprises:

[0010] a display unit having a flat image display screen for displaying a two-dimensional picture containing a stereoscopic image; and

[0011] an image transmitting panel placed parallel to and apart from said image display screen, the image transmitting panel having a microlens array of a plurality of lenses and an effective area larger than that of the stereoscopic image contained in said two-dimensional picture, and a lens frame area surrounding a perimeter of the effective area of said microlens array, so that said image transmitting panel generates an image-formation plane for displaying a real image of said two-dimensional picture in a space located on an opposite side to said display unit with respect to said microlens array.

[0012] In one aspect of the apparatus for displaying a stereoscopic two-dimensional picture according to the invention, said microlens array is a micro-convex-lens board formed of a plurality of lens systems each consisting of a pair of convex lenses coaxially arranged. The lens systems are arranged in the two-dimensional manner so that the optical axes of the lens systems are parallel to one another.

[0013] In another aspect of the apparatus for displaying a stereoscopic two-dimensional picture according to the invention, said microlens array forms an erect real image of the two-dimensional picture.

[0014] In a further aspect of the apparatus for displaying a stereoscopic two-dimensional picture according to the invention, said lens frame area is a dark color area.

[0015] In still another aspect of the invention, the apparatus for displaying a stereoscopic two-dimensional picture further comprises a supporting member supporting said lens frame area and defining a distance between the image display screen and the image transmitting panel, at least an optical path side of the supporting member being a dark color.

[0016] In a still further aspect of the invention, the apparatus for displaying a stereoscopic two-dimensional picture further comprises a picture signal supply circuit for generating a picture signal for exhibiting an image portion other than stereoscopic images which is filled with a dark color in the two-dimensional picture to be reproduced and supplying the picture signal to said display unit.

[0017] In a further aspect of the invention, the apparatus for displaying a stereoscopic two-dimensional picture further comprises an image-formation-spot indicating unit placed adjacent to said image-formation plane.

[0018] In still another aspect of the apparatus for displaying a stereoscopic two-dimensional picture according to the invention, said display unit comprises;

[0019] a back-light illuminating unit;

[0020] a color liquid crystal display panel arranged so as to completely cover a surface of the back-light illuminating unit; and

[0021] picture signal supply unit supplying a picture signal including two-dimensional picture data and stereoscopic image data to the color liquid crystal display panel.

[0022] In a further aspect of the apparatus for displaying a stereoscopic two-dimensional picture according to the invention, said display unit further comprises;

[0023] a black-and-white liquid crystal panel unit arranged between the back-light illuminating unit and the color liquid crystal display panel; and

[0024] a mask signal generating-supplying unit generating a mask signal for masking an image portion except for stereoscopic image portions to be reproduced and supplying the mask signal to the black-and-white liquid crystal panel unit.

[0025] A method for displaying a stereoscopic two-dimensional picture according to the invention comprises the steps of:

[0026] providing a display unit having a flat image display screen for displaying a two-dimensional picture containing a stereoscopic image;

[0027] arranging an image transmitting panel parallel to and apart from said image display screen, said image transmitting panel having a microlens array of a plurality of lenses and an effective area larger than that of the stereoscopic image contained in said two-dimensional picture, and a lens frame area surrounding a perimeter of the effective area of said microlens array; and

[0028] defining a relative position relationship between said image display screen and said image transmitting panel so that said image transmitting panel generates an image-formation plane for displaying a real image of said two-dimensional picture in a space located on an opposite side to said display unit with respect to said microlens array.

[0029] In one aspect of the invention, the method for displaying a stereoscopic two-dimensional picture further comprises a step of supplying a picture signal to said display unit so as to make an image other than the stereoscopic image a two-dimensional picture in a dark color.

[0030] In another aspect of the invention, the method for displaying a stereoscopic two-dimensional picture further comprises a step of placing an image-formation-spot indicating unit adjacent to said image-formation plane.

[0031] In a further aspect of the invention, the method for displaying a stereoscopic two-dimensional picture further comprises a step of:

[0032] introducing, for said display unit, a back-light illuminating unit, and a color liquid crystal display panel arranged so as to completely cover a surface of the back-light illuminating unit, and a black-and-white liquid crystal panel unit arranged between the back-light illuminating unit and the color liquid crystal display panel;

[0033] supplying a picture signal including two-dimensional picture data and stereoscopic image data to the color liquid crystal display panel;

[0034] generating a mask signal for masking an image portion except for stereoscopic image portions to be reproduced; and

[0035] supplying the mask signal to the black-and-white liquid crystal panel unit.

[0036] According to the present invention, by the microlens array, a erected real image contained in the two-dimensional picture is formed on the image-formation plane in a space without providing any diffuser such as a screen for a viewer looking squarely at, because the microlens array is secured so that the image display screen displaying the two-dimensional picture containing the stereoscopic image coincides with the focal surface of the micro convex lens array on the object side. As a result, a very simple configuration for the displaying apparatus realizes a stereoscopic exhibition of the two-dimensional picture containing the stereoscopic image. In addition, unlike the conventional methods, the present displaying apparatus does not require any polarizing glasses nor plates without deteriorating the resolution of the stereoscopic image.

[0037] The present displaying apparatus for a stereoscopic image can be configured easily by combining a two-dimensional (flat) display therewith, because a microlens array is comparatively low in price and suited for mass production.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038]FIG. 1 is a schematic sectional view of a stereoscopic image displaying apparatus according to the present invention;

[0039]FIG. 2 is a partial sectional view of a microlens array of the stereoscopic image displaying apparatus according to the present invention;

[0040]FIG. 3 is a schematic perspective view of the stereoscopic image displaying apparatus according to the present invention;

[0041]FIG. 4 is a sectional view along line A-A shown in FIG. 5;

[0042]FIG. 5 is a front view of a stereoscopic image displaying apparatus of another embodiment according to the present invention; and

[0043]FIG. 6 is a schematic perspective view of a stereoscopic image displaying apparatus of still another embodiment according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] Several embodiments of apparatuses for displaying a two-dimensional picture containing a stereoscopic image according to the present invention will be described below with reference to the accompanying drawings.

[0045]FIG. 1 is a sectional view of an apparatus for displaying a two-dimensional picture containing a stereoscopic image as a first embodiment. The apparatus comprises a display unit 10 such as a color liquid crystal display device (LCD) and an image transmitting panel 20 supported by a supporting member 15 which is fixed to the display unit. The image transmitting panel 20 generates an image-formation plane 30 in a space located on the opposite side of the LCD.

[0046] The display unit 10 includes a flat image display screen for displaying the two-dimensional picture containing the stereoscopic image. The display unit is not limited to an LCD. For example, a CRT, a plasma display, or an organic electroluminescence display is also usable for the display unit in place of the LCD. In the case where the display unit 10 is an LCD, the LCD comprises a color liquid crystal display panel 10 a having a flat image display screen, a back-light illuminating unit 10 b, and a color liquid crystal drive circuit 10 c connected to the liquid crystal display panel 10 a and driving it. The drive circuit 10 c is connected to a picture signal supply unit 11 which supplies a picture signal for the two-dimensional picture containing the stereoscopic image.

[0047] The image transmitting panel 20 comprises a microlens array 22 and a lens frame area 23, for example, a lens frame surrounding an effective area of the microlens array. The supporting member 15 supports the lens frame area 23 and defines a distance between the image display screen and the image transmitting panel. The image transmitting panel 20 is located parallel to and apart from the image display screen of the color liquid crystal display panel 10 a. The microlens array 22 is an erecting optical system in which the stereoscopic two-dimensional picture appearing on the image display screen is transmitted to a front space as a real image whose spatial orientation and size are substantially identical to that of the picture to present the real image to the view. The microlens array 22 has an effective area larger than that of the stereoscopic image contained in the two-dimensional picture. In this embodiment, the effective area of the microlens array 22 is the same as the area of the image display screen of the color liquid crystal display panel 20 a. The lens frame area 23 is in a dark color such as black so as to make the existence of the microlens array less conspicuous to the viewer.

[0048] The microlens array 22 comprises a plurality of microlenses arranged two-dimensionally. As is shown in FIG. 1, the microlens array 22 is a micro-convex-lens board formed by integrating every pair of lens-array half bodies 24 with a spacer. The micro-convex-lens board is formed of a plurality of lens systems. Each lens system includes of a pair of convex lenses coaxially arranged in the optical axes thereof. The lens systems are arranged in a two-dimensional manner so that the optical axes of the lens systems are parallel to one another. FIG. 2 is a sectional view of the microlens array 22 sectioned at a plane containing optical axes 26 of each convex lens 25. The convex lens 25, which is formed on the right side face of the lens-array half body 24 shown on the right side of the figure, has a curvature larger than that of other convex lenses. Distance L2, which is the distance between the focus of the lens-array half body 24 on the image side (image-formation plane 30) shown on the right side of the figure and the lens surface, is longer than distance L1, which is the distance between the color liquid crystal display panel 10 a of the lens-array half body 24 shown on the left side of the figure and the lens surface. Accordingly, the image-formation plane 30 is sufficiently distant from the image transmitting panel 20, making it possible for the apparatus to display a compact image by reducing the depth thereof. As shown in FIG. 2, each convex lens 25 has the same quality of material and shape. For example, the convex lenses 25 are formed to align adjoining each other in the form of a matrix on a transparent flat plate. The optical axis 26 of the convex lens 25 coincides with each other between a pair of adjacent half bodies 24 of the lens array. Although the material of the convex lens 25 and the transparent flat plate 27 is acrylic resin, the transparent flat plate may be made of glass.

[0049] The operation of the apparatus embodiment to display an image will be described below.

[0050] As shown in FIG. 3, the LCD 10 is arranged on a dark colored stage 19, such as a black color. The LCD 10 has a color liquid crystal display panel 10 a for displaying a two-dimensional picture containing a stereoscopic image, with a perimeter 10 d which is colored black. Supporting plates, being the supporting member 15, are fixed perpendicularly on the perimeter of the color liquid crystal display panel 10 a of the LCD 10 so as to screen the field of vision in the horizontal direction. The supporting member 15, too, at least the inside thereof on the side of the color liquid crystal display panel 10 a, is colored black. Provided on the free end of the supporting plates are carry units 15 a at the lower end thereof, and spring units 15 b at the upper part thereof, which are able to impart springiness in the horizontal direction opposing each other.

[0051] The lens frame area 23 of the image transmitting panel 20 is inserted in the clamped manner between the spring units 15 b, and the image transmitting panel is mounted on the carry units 15 a so as to be arranged parallel to and apart from the image display screen of the LCD 10. Because the lens frame area 23 is black, the supporting member 15 is concealed from the viewing side. The image display screens of the image transmitting panel 20 and the LCD 10 are previously arranged in a physical relationship wherein the image display screens are made to coincide with the focal surface of the microlens array 22 on the object side. In this manner, when the image of an object (stereoscopic image) is formed on the image display screen of the LCD 10, the image is formed on the focal surface on the image side, enabling a real image of the stereoscopic image to be viewed from the substantial optical axis direction. In this case, the side of the image display screen is the object side because the reproduced image is obtained from the stereoscopic image formed on the image display screen of the LCD 10.

[0052] The two-dimensional picture containing the stereoscopic image to be displayed can be perceived as a three-dimensional image, if the image other than the stereoscopic image such as the background is filled with a dark color such as black by using a known picture-signal processing method for bracketing the stereoscopic image according to the luminance level or color level. Such a processing makes only the stereoscopic image to be displayed (real image) seen to be standing out toward the viewer, because the stereoscopic image surrounded by a dark color such as black, of the perimeter 10 d of the color liquid crystal display panel 10 a and the inside of the supporting member 15. As the subject of a stereoscopic image, a dynamic body such as a moving animal or vehicle is preferable to a static body.

[0053] Furthermore, the apparatus for displaying a stereoscopic two-dimensional picture may also include an image-formation-spot indicating unit i.e., a real body 31 placed adjacent to the image-formation plane. By arranging the real body 31, a viewer can stereoscopically perceive a stereoscopic two-dimensional picture, though he does not receive any parallax image information. The real body 31 is placed in the neighborhood i.e., before and behind the image-formation plane 30 with a real image P of the stereoscopic image generated thereon so as not to obstruct the optical path. The real body 31 near the real image P is to give the viewer an illusion as if the two-dimensional picture were a real three-dimensional image.

[0054] In the first embodiment above, the description has been given of the case wherein the image transmitting panel 20 is fixed to the perimeter of the color liquid crystal display panel 10 a of the LCD 10 in a freely demountable manner with the supporting member 15. In addition to the first embodiment, FIGS. 4 and 5 show a second embodiment. It is possible to replace the supporting member 15 by an integral housing 40 as an expanded supporting member. The integral housing 40 surrounds the optical path and supports the side of the image transmitting panel 20. The internal surface of the housing 40 is colored a dark color such as black at least on the side of the optical path. It is preferable to make the width of the display screen of the color liquid crystal display panel 10 a nearly equal to an effective width of the microlens array 22 , that is, to make the effective areas of both almost the same. In order to realize this state, slit units 41 respectively corresponding to the thickness of the image transmitting panel 20 and the color liquid crystal display panel 10 a are provided inside the integral housing 40, and each of them is inter-fitted so as to be fixed apart from each other by a predetermined distance. Owing to this configuration, it is unnecessary to color the lens frame area 23 in the perimeter of the microlens array 22 black. Instead, a front face 40 a of the housing 40 is colored a dark color. It is also possible to provide a circuit housing unit 43 inside the integral housing 40 on the side of the back face of the color liquid crystal display panel 10 a so as to house the drive circuit and other parts. A compact apparatus for displaying a stereoscopic image is realized with the configuration described above.

[0055] In a third embodiment, the picture signal supply unit 11 of the apparatus for displaying the stereoscopic two-dimensional picture may include an electric circuit for generating a modified picture signal for exhibiting an image portion other than stereoscopic images which is filled with a dark color in the two-dimensional picture to be reproduced and then supplying it to the drive circuit and the display unit so as to form only the stereoscopic image.

[0056] In a fourth embodiment, the display unit 10 can comprise a back-light illuminating unit 10 b, a color liquid crystal display panel 10 a arranged so as to cover the whole surface of the back-light lighting, and a black-and-white liquid crystal panel unit 12 arranged between the back-light illuminating unit 10 b and the color liquid crystal display panel 10 a, as shown in FIG. 6, in addition to the first embodiment. In this case, the apparatus for displaying a stereoscopic two-dimensional picture includes a black-and-white liquid crystal drive circuit 10 f connected to the black-and-white liquid crystal panel unit 12 and a mask signal generating-supplying unit 10 g connected to the black-and-white liquid crystal drive circuit 10 f. The mask signal generating-supplying unit 10 g is connected to the picture signal supply unit 11 for supplying a picture signal including two-dimensional picture data with stereoscopic image data contained therein. The mask signal generating-supplying unit 10 g generates a mask signal for masking an image portion except for stereoscopic image portions to be reproduced from the picture signal on the basis of the supplied data from the picture signal supply unit 11, and supplies the mask signal to the black-and-white liquid crystal drive circuit 10 f. With this embodiment configuration, when the color liquid crystal drive circuit 10 c drives the color liquid crystal display panel 10 a so as to form an original picture i.e., the two-dimensional picture containing the stereoscopic image, then the black-and-white liquid crystal drive circuit 10 f simultaneously drives the black-and-white liquid crystal panel unit 12 so as to mask an image portion except the stereoscopic image corresponding to the mask signal, for example, a background image. Consequently, the two-dimensional picture containing the stereoscopic image to be displayed can have images such as background images colored dark, such as black, except for the stereoscopic image.

[0057] In a fifth embodiment, instead of the black-and-white liquid crystal panel unit 12 and the drive circuit 10 f of the fourth embodiment, a mask processing circuit 10 h connected to the picture signal supply unit 11, the mask signal generating-supplying unit 10 g and the color liquid crystal drive circuit 10 c may be provided with the apparatus as indicated by dotted lines shown in FIG. 6. The mask signal generated in the mask signal generating-supplying unit 10 g is supplies to the mask processing circuit 10 h as indicated by a dashed arrow shown in FIG. 6. The mask processing circuit 10 h generates a picture signal for a picture masked except the stereoscopic image part on the basis of the supplied signals from the picture signal supply unit 11 and the mask signal generating-supplying unit 10 g, and supplies the generated picture signal to the color liquid crystal drive circuit 10 c.

[0058] It is understood that the foregoing description and accompanying drawings set forth the preferred embodiments of the invention at the present time. Various modifications, additions and alternative designs will, of course, become apparent to those skilled in the art in light of the foregoing teachings without departing from the spirit and scope of the disclosed invention. Thus, it should be appreciated that the invention is not limited to the disclosed embodiments but may be practiced within the full scope of the appended claims. 

What is claimed is:
 1. An apparatus for displaying a stereoscopic two-dimensional picture comprising: a display unit having a flat image display screen for displaying a two-dimensional picture containing a stereoscopic image; and an image transmitting panel placed parallel to and apart from said image display screen, the image transmitting panel having a microlens array of a plurality of lenses and an effective area larger than that of the stereoscopic image contained in said two-dimensional picture, and a lens frame area surrounding a perimeter of the effective area of said microlens array, so that said image transmitting panel generates an image-formation plane for displaying a real image of said two-dimensional picture in a space located on an opposite side to said display unit with respect to said microlens array.
 2. An apparatus for displaying a stereoscopic two-dimensional picture according to claim 1 , wherein said microlens array is a micro-convex-lens board formed of a plurality of lens systems each consisting of a pair of convex lenses coaxially arranged, the lens systems being arranged in the two-dimensional manner so that the optical axes of the lens systems are parallel to one another.
 3. An apparatus for displaying a stereoscopic two-dimensional picture according to claim 2 , wherein said microlens array forms an erect real image of the two-dimensional picture.
 4. An apparatus for displaying a stereoscopic two-dimensional picture according to claim 1 , wherein said lens frame area is a dark color area.
 5. An apparatus for displaying a stereoscopic two-dimensional picture according to claim 1 , further comprising a supporting member supporting said lens frame area and defining a distance between the image display screen and the image transmitting panel, at least an optical path side of the supporting member being a dark color.
 6. An apparatus for displaying a stereoscopic two-dimensional picture according to claim 1 , further comprising a picture signal supply circuit for generating a picture signal for exhibiting an image portion other than stereoscopic images which is filled with a dark color in the two-dimensional picture to be reproduced and supplying the picture signal to said display unit.
 7. An apparatus for displaying a stereoscopic two-dimensional picture according to claim 1 , further comprising an image-formation-spot indicating unit placed adjacent to said image-formation plane.
 8. An apparatus for displaying a stereoscopic two-dimensional picture according to claim 1 , wherein said display unit comprises; a back-light illuminating unit; a color liquid crystal display panel arranged so as to completely cover a surface of the back-light illuminating unit; and picture signal supply unit supplying a picture signal including two-dimensional picture data and stereoscopic image data to the color liquid crystal display panel.
 9. An apparatus for displaying a stereoscopic two-dimensional picture according to claim 8 , wherein said display unit further comprises; a black-and-white liquid crystal panel unit arranged between the back-light illuminating unit and the color liquid crystal display panel; and a mask signal generating-supplying unit generating a mask signal for masking an image portion except for stereoscopic image portions to be reproduced and supplying the mask signal to the black-and-white liquid crystal panel unit.
 10. A method for displaying a stereoscopic two-dimensional picture comprising the steps of: providing a display unit having a flat image display screen for displaying a two-dimensional picture containing a stereoscopic image; arranging an image transmitting panel parallel to and apart from said image display screen, said image transmitting panel having a microlens array of a plurality of lenses and an effective area larger than that of the stereoscopic image contained in said two-dimensional picture, and a lens frame area surrounding a perimeter of the effective area of said microlens array; and defining a relative position relationship between said image display screen and said image transmitting panel so that said image transmitting panel generates an image-formation plane for displaying a real image of said two-dimensional picture in a space located on an opposite side to said display unit with respect to said microlens array.
 11. A method for displaying a stereoscopic two-dimensional picture according to claim 10 , further comprising a step of generating a picture signal for exhibiting an image portion other than stereoscopic images which is filled with a dark color in the two-dimensional picture to be reproduced and supplying the picture signal to said display unit.
 12. A method for displaying a stereoscopic two-dimensional picture according to claim 10 , further comprising a step of placing an image-formation-spot indicating unit adjacent to said image-formation plane.
 13. A method for displaying a stereoscopic two-dimensional picture according to claim 10 , further comprising a step of: introducing, for said display unit, a back-light illuminating unit, a color liquid crystal display panel arranged so as to completely cover a surface of the back-light illuminating unit, and a black-and-white liquid crystal panel unit arranged between the back-light illuminating unit and the color liquid crystal display panel; supplying a picture signal including two-dimensional picture data and stereoscopic image data to the color liquid crystal display panel; generating a mask signal for masking an image portion except for stereoscopic image portions to be reproduced; and supplying the mask signal to the black-and-white liquid crystal panel unit. 